Damper assembly for air handling system

ABSTRACT

A damper assembly and method is provided for readily installing the damper assembly into an air duct of an existing air handling system to regulate air flow through the air duct. The damper assembly includes a mounting plate and a damper plate movably attached to the mounting plate. The mounting plate may include plurality of spaced apart through holes adjacent one end for securing the mounting plate to the air duct with a fastener. The damper assembly further includes means for movably attaching the damper plate to the mounting plate and means for adjusting the position of the damper plate within the air duct. The damper assembly is inserted into the outlet end of the air duct and the mounting plate is mounted with the damper plate positioned within the air duct. The position of the damper plate is adjusted to provide the desired air flow through the air duct.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a damper assembly for an airhandling system. More particularly, the present invention is a damperassembly configured to be readily installed within an air duct of anexisting air handling system and operable for regulating air flowthrough the air duct.

2. Technical Background

Conventional air handling systems, such as heating, ventilating and airconditioning (HVAC) systems, include a central air plenum and aplurality of air ducts extending outwardly from the central air plenumto distribute air flow into a large open area, or into different roomsin a home or building. At the time of installation, a damper assemblymay be provided in each air duct to adjust the air flow through the airduct. In a typical installation, the damper assembly is positioned inthe air duct adjacent the central air plenum and manually adjusted by anexternal handle or lever. However, access to the various damperassemblies to change the air flow distribution throughout the system isoften restricted. Alternatively, each air duct may terminate away fromthe central air plenum in a grate having movable shutters, commonlyreferred to as an “air diffuser.” An air diffuser, however, cannoteffectively handle a high flow rate without making a whistling noisewhen moved to a closed position.

U.S. Pat. No. 5,207,615 issued to Edmisten discloses an air handlingsystem having a central air plenum and a plurality of air ducts. Eachair duct is provided with a damper assembly positioned in the air ductaway from the central air plenum and adjacent the outlet end of the airduct. The damper assembly includes a damper plate pivotally mountedwithin the air duct about a pivot axis such that the damper plate can beadjusted between a closed position substantially transverse to the airduct and an opened position substantially parallel to the air duct. Thedamper assembly is positioned within the air duct at a locationaccessible from the outlet end so that a person may manually pivot thedamper plate to regulate the air flow through the air duct. The damperassembly is configured to be positioned within an air duct at the timethe air handling system is installed and is operable for regulating airflow through the air duct. However, the damper assembly of the '615patent cannot be installed within an air duct of an existing airhandling system without dismantling and subsequently reconstructing theair duct and surrounding infrastructure. In particular, no means isprovided for readily installing the damper assembly in an existing airhandling system.

Accordingly, what is needed is a damper assembly configured to bereadily installed within an air duct of an existing air handling systemand operable for regulating air flow through the air duct. Moreparticularly, a damper assembly is needed for an air handling systemhaving at least one air duct where air flow adjustments are necessaryand there is no means of readily installing a conventional damperassembly for regulating air flow through the air duct. A damper assemblyaccording to the present invention satisfies this need, among others,while providing a method of readily retrofitting an existing airhandling system having at least one air duct to include a damperassembly positioned within the air duct and operable for regulating airflow through the air duct.

SUMMARY OF THE INVENTION

In one aspect, the invention provides a damper assembly for regulatingair flow through an air duct. The damper assembly includes a mountingplate for mounting the damper assembly to the air duct and a damperplate movably attached to the mounting plate. The mounting plate isinserted into the air duct and mounted adjacent an outlet end of the airduct. The mounting plate may be provided with a hook at one end forengaging the air duct, and more particularly, a boot collar disposedbetween the air duct and a boot. The mounting plate may also be providedwith at least one through hole for receiving a fastener to secure themounting plate to the air duct. More preferably, the mounting plate hasa plurality of spaced apart through holes, at least one of the throughholes receiving a fastener to secure the mounting plate to the air duct.The damper assembly further includes means for movably attaching thedamper plate to the mounting plate and means for adjusting the positionof the damper plate within the air duct. In a preferred embodiment, themounting plate is relatively thin and has an elongate, generallyrectangular shape and the damper plate is relatively thin and has agenerally circular shape.

In another aspect, the present invention provides a damper assemblyincluding a mounting plate adapted for mounting adjacent an outlet endof the air duct, a damper plate movably attached to the mounting plate,means for movably attaching the damper plate to the mounting plate andmeans for adjusting the position of the damper plate within the airduct. The mounting plate is inserted into the outlet end of the air ductto install the damper assembly into an air duct of an existing airhandling system. The means for movably attaching the damper plate to themounting plate preferably includes a first mounting bracket attached tothe damper plate and a second mounting bracket attached to the mountingplate by a pair of fasteners. Each fastener preferably consists of anexternally threaded bolt, and internally threaded nut and a wave washersuch that the first mounting bracket of the damper plate is attached tothe second mounting bracket of the mounting plate with sufficientresistance to maintain the damper plate in a desired position within theair duct against forces generated by air flow through the air duct,while at the same time permitting the position of the damper plate to beadjusted without requiring the damper assembly to be disassembled. Themeans for adjusting the position of the damper plate preferably includesa bracket attached to the damper plate and having a flange portionextending outwardly from the damper plate.

In yet another aspect, the present invention provides a method ofinstalling a damper assembly into an air duct of an existing airhandling system. The method includes providing a damper assembly havinga mounting plate and a damper plate movably attached to the mountingplate. The damper assembly is inserted into an outlet end of the airduct and the mounting plate is mounted to the air duct adjacent theoutlet end. The method may further include providing means for movablyattaching the damper plate to the mounting plate. The means for movablymounting the damper plate to the mounting plate preferably includes afirst mounting bracket attached to the damper plate and a secondmounting bracket attached to the mounting plate by a pair of fasteners.The fasteners preferably consist of an externally threaded bolt, andinternally threaded nut and a wave washer such that the first mountingbracket of the damper plate is attached to the second mounting bracketof the mounting plate with sufficient resistance to maintain the damperplate in a desired position within the air duct against forces generatedby air flow through the air duct, while at the same time permitting theposition of the damper plate to be adjusted without requiring the damperassembly to be disassembled. The method may further include providingmeans for adjusting the position of the damper plate within the airduct. The means for adjusting the damper plate preferably includes abracket attached to the damper plate and having a flange portionextending outwardly from the damper plate.

Additional features and advantages of the invention will be set forth inthe following detailed description, and in part will be readily apparentto those skilled in the art from that description or recognized bypracticing the invention as described herein, including the accompanyingdrawings and the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description present exemplary embodiments of theinvention, and are intended to provide an overview or framework forunderstanding the nature and character of the invention as it isclaimed. The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated into and constitutea part of this specification. The drawings illustrate variousembodiments of the invention, and together with the detaileddescription, serve to explain the principles and operations thereof

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a preferred embodiment of a damperassembly according to the present invention prior to being installedinto an air duct of an existing air handling system.

FIG. 2 is a perspective view showing the damper assembly of FIG. 1installed within the air duct with the damper plate in a fully openedposition.

FIG. 3 is a perspective view showing the damper assembly of FIG. 1installed within the air duct with the damper plate in a fully closedposition.

FIG. 4 is a perspective view illustrating a means for adjusting theposition of the damper plate within the air duct.

FIG. 5 is an exploded view showing a preferred embodiment of a damperassembly according to the present invention in greater detail.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in greater detail to presently preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings. Whenever possible, the same reference numeralswill be used throughout the drawings to refer to the same or like parts.An exemplary and preferred embodiment of a damper assembly 20 accordingto the invention is shown in FIG. 1 with the damper assembly outside anair duct 10 of an existing air handling system prior to installing thedamper assembly into the air duct. As used herein, “existing airhandling system” refers to an air handling system such as a commonlyused heating, ventilating and air conditioning (HVAC) system, that isalready (i.e., previously) installed and in which air flow adjustmentsare needed, but for which there is no means of readily installing aconventional damper assembly for regulating air flow through an airduct. Accordingly, the present invention provides a method for readilyretrofitting an existing air handling system having at least one airduct to include a damper assembly positioned within the air duct andoperable for regulating air flow through the air duct.

Referring now specifically to FIGS. 1-3, the air duct 10 extendsoutwardly from a central air plenum (not shown) of the previouslyinstalled air handling system into a large open area, or into a room ofa home or building. The air duct 10 terminates in an outlet endtypically comprising a boot 12 and a boot collar 14 for joining the bootto the outlet end of the air duct. As shown herein, the air duct 10transitions from a generally circular cross-section at the outlet end ofthe air duct to a generally rectangular cross-section at the outlet endof the boot 12. The outlet end of the boot 12 typically extends throughan opening formed in a floor or wall 15 of the room such that air flowthrough the air duct 10 is delivered to the room. The outlet end of theboot 12 is rectangular shaped in order to receive a conventional gratehave movable shutters, as will be described in greater detail below.However, the outlet end of the air duct 10 and/or boot 12 may have anydesired cross-sectional shape, for example circular, square,rectangular, elliptical, etc. The present invention is not limited bythe specific size, shape and location of the outlet end of the air duct10. The only requirement is that the outlet end of the air duct 10 isaccessible from the interior of the room and that the damper assembly 20is suitably sized and shaped to be inserted into the outlet end of theair duct from the room and conforms to the interior geometry of the airduct.

Referring now specifically to FIG. 1, the damper assembly 20 comprises adamper plate 22 and a mounting plate 24. The damper plate 22 is movablyattached to the mounting plate 24. As shown and described herein, thedamper plate 22 is relatively thin and generally circular in shape,while the mounting plate 24 is relatively thin, elongate and generallyrectangular in shape. The damper plate 22 and the mounting plate 24 maybe made of any suitable material, such as plastic, composite or metal.Preferably, however, the damper plate 22 and the mounting plate 24 aremade of the same lightweight and formable metal, such as aluminum. Inparticular, the mounting plate 24 should be substantially rigid, but atthe same time capable of being formed to match the contour of the boot12, as will be described. The damper plate 22, on the other hand, mustbe rigid enough to withstand forces generated by air flow through theair duct 10 without buckling or deforming appreciably. In practice, thegeometric properties of the damper plate 22 and the mounting plate 24contribute to their desired degree of stiffness. The damper plate 22 maybe movably attached to the mounting plate 24 at any location such thatthe damper plate engages the outlet end of air duct 10 to regulate airflow through the air dust, as will be described in greater detail below.As shown, the damper plate 22 is movably attached to the mounting plate24 at one end. However, the damper plate 22 may be movably attached tothe mounting plate 24 at a medial location between the opposite ends ofthe mounting plate. The mounting plate 24 may also be provided with oneor more through holes 26 adjacent the end opposite the damper plate 22,for a purpose to be described.

FIG. 2 is a perspective view showing the damper assembly 20 installedwithin the air duct 10 with the damper plate 22 in a fully openedposition. The damper assembly 20 is inserted into the outlet end of theboot 12 from the interior of the room and positioned with the damperplate 22 adjacent the outlet end of the air duct 10. Typically, thedamper assembly 20 is inserted into the boot 12 until the end of themounting plate 24 having the movably attached damper plate 22 ispositioned adjacent a lip 13 of the boot collar 14 that meets the outletend of the air duct 10. As shown, the end of the mounting plate 24 isprovided with a hook 25 or other suitable means for engaging the lip 13of the boot collar 14. The hook 25 is particularly useful to secure theend of the mounting plate 24 adjacent the damper plate 22 to the airduct 10 without special tools or equipment at a location within the airduct that is not accessible for a conventional fastener, such as a sheetmetal screw. The mounting plate 24 is configured with sufficient lengthsuch that the end of the mounting plate opposite the damper plate 22will typically extend outwardly from the outlet end of the boot 12. Themounting plate 24 may be provided with a series of spaced through holes26 so that an appropriate one (or more) of the through holes may beutilized to secure the mounting plate to the interior of the boot 12adjacent the outlet end with a common fastener 27, such as a sheet metalscrew. Alternatively, the mounting plate 24 may be secured to the boot12 by any other suitable means, such as adhesive, or by one or morerivets in the event sufficient access to the exterior of the boot 12 isavailable. Any excess length of the mounting plate 24, indicated bybroken lines in FIG. 2, is removed (e.g. cut off) and discarded. Thestructural arrangement of the damper assembly 20 and the method ofinstalling the damper assembly into the air duct 10 of an existing airhandling system described herein represent the best mode of practicingthe invention presently known to the inventor. However, many otherstructural arrangements and installations are possible and would beknown or readily ascertained by one of ordinary skill in the art.Accordingly, any such structural arrangements and/or installationmethods are considered to fall within the intended scope of the presentinvention.

FIG. 3 is a perspective view showing the damper assembly 20 installedwithin the air duct 10 with the damper plate 22 in a fully closedposition. As previously mentioned, the damper plate 22 is movablyattached to the mounting plate 24. Any suitable means 30 for movablymounting the damper plate 22 to the mounting plate 24 may be employed.The means 30 for movably mounting the damper plate 22 providessufficient resistance to maintain the damper plate in a desired positionwithin the air duct 10 against forces generated by air flow through theair duct, while at the same time permitting the position of the damperplate 22 to be adjusted without requiring the damper assembly 20 to bedisassembled. In particular, the means 30 permits the damper plate 22 tobe repositioned from the room without loosening or detaching the damperplate from the mounting plate 24. For example, a person may adjust thedamper plate 22 from the substantially opened position shown in FIG. 2to the substantially closed position shown in FIG. 3 to restrict airflow into the room by reaching into the boot 12 and manipulating thedamper plate 22 by hand. Preferably, the damper plate 22 is providedwith a bracket 28 or other suitable structure that serves as a means forgrasping and manipulating the damper plate. As shown, a generallyL-shaped bracket 28 is fixed to the damper plate 22 by a fastener, rivetor adhesive, and has an opening 29 through the flange portion extendingoutwardly from the damper plate in the direction of the boot 12.However, any alternative means, for example a handle, rod or chain,suitable for adjusting the position of the damper plate 22 within theair duct may be utilized.

FIG. 4 is a perspective view illustrating a preferred means foradjusting the position of the damper plate 22 within the air duct 10utilizing the bracket 28. The means illustrated in FIG. 4 isparticularly useful when the outlet end of the boot 12 is covered by agrate 16 having at least one, and preferably, a plurality of movableshutters 17 for restricting air flow into the room. The grate 16 andshutters 17 are commonly referred to as an “air diffuser,” indicated byphantom lines in FIG. 4. Without a damper assembly 20 according to thepresent invention installed within the air duct 10, a conventional airdiffuser tends to make an annoying whistling noise when the shutters 17are moved to a closed position due to the air flow being forced throughthe air duct. With the damper assembly 20 installed, the force of theair flow can be substantially reduced by the damper plate 22 beforereaching the air diffuser. Since the air diffuser is typically securedto the boot 12 by a plurality of fasteners, such as sheet metal screws,it is desirable to be able to adjust the position of the damper plate 22without removing the air diffuser to provide sufficient access tomanually manipulate the damper plate. Accordingly, an elongate rod 18may be provided with a generally L-shaped end for engaging the opening29 through the flange portion of the bracket 28. The shutters 17 of theair diffuser are opened and the rod 18, indicated by broken lines inFIG. 4, is inserted into the boot 12 between adjacent shutters andhooked onto the bracket 28 by threading the end of the rod through theopening 29. The rod 18 is then manipulated to position the damper plate22 within the air duct 10 to regulate the air flow through the air duct.The rod 18 may be removed once the damper plate 22 is positioned, or mayremain engaged with the bracket 28 until the shutters 17 need to beclosed.

FIG. 5 is an exploded view showing a preferred embodiment of a damperassembly according to the present invention in greater detail. Thedamper plate 22 (including bracket 28) and the mounting plate 24 are aspreviously described, and accordingly, will not be described furtherwith reference to FIG. 5. However, an exemplary means 30 for movablymounting the damper plate 22 to the mounting plate 24 is shown and willbe described in greater detail. The particular means 30 shown in FIG. 5comprises a first mounting bracket 32 and a second mounting bracket 34.The first mounting bracket 32 is attached to the damper plate 22 and thesecond mounting bracket 34 is attached to the mounting plate 34 in asuitable manner, such as a fastener, rivet or adhesive. As shown, thefirst mounting bracket 32 is secured to the damper plate 22 by a pair offasteners, while the second mounting bracket 34 is secured to themounting plate 34 by a pair of rivets. Regardless, each mounting bracket32, 34 has a pair of outwardly extending flanges having openings 35 forreceiving fasteners to movably attach the damper plate 22 to themounting plate 34. Each fastener preferably comprises an externallythreaded bolt 36, an internally threaded nut 37 and a non-flat washer 38between the bolt and nut commercially known as a “wave washer.” Suchwave washers are known and available from most commercial hardwaresuppliers. The wave washer 38 provides a sufficient resistance force tomaintain the damper plate 22 in a desired position within the air duct10 against forces generated by air flow through the air duct, whilepermitting the position of the damper plate 22 to be adjusted aspreviously described. Without utilizing the wave washer 38, the damperplate 22 would necessarily be attached to the mounting plate 24 eithertoo loosely to maintain the position of the damper plate within the airduct 10, or to securely to permit the position of the damper plate to beadjusted without disassembling the damper assembly 20. Utilizing thewave washer 38 provides a desirable degree of frictional resistance thatis somewhat variable by adjusting the tightness of the nut 37 on thebolt 36.

The embodiments described above provide numerous advantages over anyknown damper assembly for regulating air flow through an air duct of anair handling system. In particular, a damper assembly according to thepresent invention may be readily installed in an air duct of an existingair handling system when no means of installing a conventional balancingdamper is available. Furthermore, the position of the damper plate ofthe damper assembly can be easily adjusted to regulate air flow throughthe air duct from a room without the use of tools. In an exemplary andpreferred embodiment, the damper plate is movably mounted to a mountingplate utilizing a wave washer that provides a desired degree ofresistance. As a result, the position of the damper plate can be easilyadjusted through an air diffuser utilizing an elongate rod withoutdetaching the air diffuser from the boot of the air duct.

Particular examples and preferred embodiments have been shown anddescribed herein for the purpose of explaining certain features andadvantages of the present invention. However, it will be apparent tothose skilled in the art that various modifications and variations canbe made to the present invention without departing from the spirit andscope of the invention. Thus, it is intended that the claims appendedhereto cover any and all modifications and variations of the inventionthat may be made by one of ordinary skill in the art, provided they comewithin the scope of the claims and their equivalents.

1. A damper assembly for regulating air flow through an air duct, thedamper assembly comprising: a mounting plate for mounting the damperassembly to the air duct; and a damper plate movably attached to themounting plate; wherein the mounting plate is inserted into the air ductand mounted adjacent an outlet end of the air duct.
 2. The damperassembly according to claim 1, wherein the mounting plate comprises ahook at one end for engaging the air duct.
 3. The damper assemblyaccording to claim 1, wherein the mounting plate has at least onethrough hole for receiving a fastener to secure the mounting plate tothe air duct.
 4. The damper assembly according to claim 1, wherein themounting plate has a plurality of spaced apart through holes, at leastone of the through holes receiving a fastener to secure the mountingplate to the air duct.
 5. The damper assembly according to claim 1,further comprising means for adjusting the position of the damper platewithin the air duct.
 6. The damper assembly according to claim 5,wherein the means for adjusting the position of the damper platecomprises a bracket attached to the damper plate and wherein the bracketcomprises a flange portion extending outwardly from the damper plate. 7.The damper assembly according to claim 1, wherein the mounting plate isrelatively thin and has an elongate, generally rectangular shape andwherein the damper plate is relatively thin and has a generally circularshape.
 8. The damper assembly according to claim 1, further comprisingmeans for movably attaching the damper plate to the mounting plate. 9.The damper assembly according to claim 7, wherein the means for movablyattaching the damper plate to the mounting plate comprises a firstmounting bracket attached to the damper plate and a second mountingbracket attached to the mounting plate and wherein each of the firstmounting bracket and the second mounting bracket has a pair of openingsfor receiving fasteners.
 10. The damper assembly according to claim 9,wherein the fasteners comprise an externally threaded bolt, andinternally threaded nut and a wave washer.
 11. A damper assemblycomprising: a mounting plate adapted for mounting adjacent an outlet endof the air duct; a damper plate movably attached to the mounting plate;means for movably attaching the damper plate to the mounting plate; andmeans for adjusting the position of the damper plate within the airduct.
 12. The damper assembly according to claim 11, wherein themounting plate is inserted into the outlet end of the air duct toinstall the damper assembly into an air duct of an existing air handlingsystem.
 13. The damper assembly according to claim 11, wherein the meansfor movably attaching the damper plate to the mounting plate comprises afirst mounting bracket attached to the damper plate and a secondmounting bracket attached to the mounting plate and wherein each of thefirst mounting bracket and the second mounting bracket has a pair ofopenings for receiving fasteners.
 14. The damper assembly according toclaim 13, wherein the fasteners comprise an externally threaded bolt,and internally threaded nut and a wave washer.
 15. The damper assemblyaccording to claim 11, wherein the means for adjusting the position ofthe damper plate comprises a bracket attached to the damper plate andwherein the bracket comprises a flange portion extending outwardly fromthe damper plate.
 16. A method of installing a damper assembly into anair duct of an existing air handling system, the method comprising:providing a damper assembly comprising a mounting plate and a damperplate movably attached to the mounting plate; inserting the damperassembly into an outlet end of the air duct; and mounting the mountingplate to the air duct adjacent the outlet end.
 17. The method accordingto claim 16, further comprising providing means for movably attachingthe damper plate to the mounting plate.
 18. The method according toclaim 17, wherein the means for movably mounting the damper plate to themounting plate comprises a first mounting bracket attached to the damperplate and a second mounting bracket attached to the mounting plate, andwherein each of the first mounting bracket and the second mountingbracket has a pair of openings for receiving fasteners.
 19. The methodaccording to claim 18, wherein the fasteners comprise an externallythreaded bolt, and internally threaded nut and a wave washer.
 20. Themethod according to claim 16, further comprising providing means foradjusting the position of the damper plate within the air duct, themeans for adjusting the damper plate comprising a bracket attached tothe damper plate, the bracket comprising a flange portion extendingoutwardly from the damper plate.